Low friction high release coatings for release tapes

Abstract

A release surface for use in diaper tape assemblies comprises a cured release coating of a reactive silicone system comprising at least 15% by weight of a reactive polydialkyl siloxane, at least 40% by weight of a defined reactive silicone high adhesion agent and a silicone crosslinking agent. Cure occurs in the presence of Group VIII metal catalyst, and cured release coating has a coefficient of friction of less than about 0.7 lb/2 inch and a release greater than 50 g/in.

I claim: 
     
       1. A release surface comprising a substrate supporting a cured release coating formed from a reactive silicone system comprising at least 15% by weight of the silicone system f a reactive polydialkyl siloxane, at least 40% by weight of the silicone system of a reactive silicone high adhesive agent, said silicone high adhesion agent comprising a copolymer of monofunctional silicone units of the formula:   R'.sub.3 SiO.sub.178     and tetrafunctional units of the formula:     SiO.sub.4/2     where R 40   is an alkyl or alkenyl group containing from 1 to about 6 carbon atoms dispersed in a reactive organic diluent and a silicone hydride crosslinking agent, cure occurring by hydrosilation reaction of the reactive silicone system, reactive diluent and silicone hydride crosslinking agent in the presence of Group VIII metal catalyst, said polydialkyl siloxane and silicone high adhesion agent being present in proportion to provide a cured release coating having a coefficient of friction of less than about 0.7 lb/2 inch and a release greater than about 50 g/in.   
     
     
       2. A release surface as claimed in claim 1 in which the reactive polydialkyl siloxane is present in an amount of from about 25 to about 50% by weight of the reactive silicone system. 
     
     
       3. A release surface as claimed in claim 1 in which the reactive polydialkyl siloxane is a polydimethyl siloxane. 
     
     
       4. A release surface as claimed in claim 1 in which the reactive polydialkyl siloxane has a viscometric average molecular weight in excess of 300,000 cps. 
     
     
       5. A release surface as claimed in claim 3 in which the reactive polydimethyl siloxane has a viscometric average molecular weight of from about 300,000 to about 1,000,000 cps. 
     
     
       6. A release surface as claimed in claim 1 in which the reactive silicone high adhesion agent is present in an amount of from about 50 to about 75% by weight of the reactive silicone system. 
     
     
       7. A release surface as claimed in claim 2 in which the reactive silicone high adhesion agent is present in an amount of from about 50 to about 75% by weight of the reactive silicone system. 
     
     
       8. A release surface as claimed in claim 3 in which the reactive silicone high adhesion agent is present in an amount of from about 50 to about 75% by weight of the reactive silicone system. 
     
     
       9. A release surface as claimed in claim 5 in which the reactive silicone high adhesion agent is present in an amount of from about 50 to about 75% by weight of the reactive silicone system. 
     
     
       10. A release surface comprising a substrate supporting a cured release coating formed from a reactive silicone system comprising from about 25 to about 50% by weight of the silicone system of an alkenyl reactive siloxane of the formula: ##STR3## wherein each R is independently an alkenyl containing from 2 to about 6 carbon atoms and m and n are independent integers; from about 75 to about 50% by weight of the silicone system of a reactive silicone high adhesion agent, said silicone high adhesion agent comprising a copolymer of monofunctional silicone units of the formula:   R'.sub.3 SiO.sub.1/2     and tetrafunctional units of the formula:     SiO.sub.4/2     where R' is an alkyl or alkenyl group containing from 1 to about 6 carbon atoms dispersed in a reactive organic diluent and a silicone hydride crosslinking agent, cure occurring by hydrosilation reaction of the reactive silicone system, reactive diluent and silicone hydride crosslinking agent in the presence of Group VIII metal catalyst, said polydialkyl siloxane and silicone high adhesion agent being present in proportion to provide a cured release coating having a coefficient of friction of less than about 0.7 lb/2 inch and a release greater than about 50 g/in.   
     
     
       11. A release surface as claimed in claim 10 in which the reactive polydialkyl siloxane is a polydimethyl siloxane. 
     
     
       12. A release surface as claimed in claim 10 in which the reactive polydialkyl siloxane has a viscometric average molecular weight in excess of 300,000 cps. 
     
     
       13. A release surface as claimed in claim 11 in which the reactive polydimethyl siloxane has a viscometric average molecular weight of from about 300,000 to about 1,000,000 cps. 
     
     
       14. In the combination of a tape face material having on one surface thereof a pressure sensitive adhesive and on the opposed surface thereof a cured release coating, the improvement which comprises providing as the cured release coating formed from a reactive silicone system comprising at least 15% by weight of the silicone system of a reactive polydialkyl siloxane, at least 40% by wight of the silicone system of a reactive silicone high adhesion agent, said silicone high adhesion agent comprising a copolymer of monofunctional silicone units of the formula:   R'.sub.3 RiO.sub.1/2     and tetrafunctional units of the formula:     SiO.sub.4/2     where R' is an alkyl or alkenyl group containing form 1 to about 6 carbon atoms dispersed in a reactive organic diluent and a silicone hydride crosslinking agent, cure occurring by hydrosilation reaction of the reactive silicone systems, reactive diluent and silicone hydride crosslinking agent in the presence of Group VIII metal catalyst, said polydialkyl siloxane and silicone high adhesion agent being present in proportion to provide a cured release coating having a coefficient of friction of less than about 0.7 lb/2 inch and a release greater than about 50 g/in.   
     
     
       15. A release surface as claimed in claim 14 in which the reactive polydialkyl siloxane is present in an amount of from about 25 to about 50% by weight of the reactive silicone system. 
     
     
       16. A release surface as claimed in claim 14 in which the reactive polydialkyl siloxane is a polydimethyl siloxane. 
     
     
       17. A release surface as claimed in claim 14 in which the reactive polydialkyl siloxane has a viscometric average molecular weight in excess of 300,000 cps. 
     
     
       18. A release surface as claimed in claim 14 in which the reactive polydimethyl siloxane has a viscometric average molecular weight of from about 300,000 to about 1,000,000 cps. 
     
     
       19. In a diaper tape construction consisting of the combination of a fastening tape and a release tape each comprising a polypropylene tape face material having on the opposed surface thereof a cured silicone release coating which comprises providing as the cured release coating a cured coating formed from a reactive silicone system comprising at least 15% by weight of the silicone system of a reactive polydialkyl siloxane, at least 40% by weight of the silicone system of a reactive silicone high adhesion agent, said silicone high adhesion agent comprising a copolymer of monofunctional silicone units of the formula:   R'.sub.3 SiO.sub.178     and tetrafunctional units of the formula:     SiO.sub.4/2     where R' is an alkyl or alkenyl group containing from 1 to about 6 carbon atoms dispersed in a reactive organic diluent and a silicone hydride crosslinking agent, cure occurring by hydrosilation reaction of the reactive silicone system, reactive diluent and silicone hydride crosslinking agent in the presence of Group VIII metal catalyst, said polydialkyl siloxane and silicone high adhesion agent being present in proportion to provide a cured release coating having a coefficient of friction of less than about 0.7 lb/2 inch and a release greater that about 50 g/in.